I've got a Korg AX1G (the original of the series, very limited in comparison to the 1000). It's cheap, it's plastic, and I swear I'm gonna snap that
expression pedal. The input jack's starting to wear out. But the effects sound decent. I used to use it as my entire rig before I got my Line6 Flextone II (i.e. used it direct into a stereo system that had a guitar input). Basically, if it seems strong enough to take the abuse you'll be giving it, the effects are decent.